The present invention relates to transversal filters and more particularly to a universal transversal filter.
The transversal filter or finite impulse response (FIR) filter, is a device which can be designed with arbitrary impulse response of finite duration to implement a wide range of linear filters. The classical transversal filter consists of a delay line which is tapped at a number of points along its length. The taps are all connected through separate gain setting or selection circuits to a summing network. By properly selecting the gain of each of the gain setting circuits, the desired finite impulse response can be obtained. While such transversal filters are useful, for instance as high pass, low pass or band pass filters, they have the drawback in that any change in function performed by the filter requires a change in the gain setting circuits, thus requiring a different filter design for each new function to be performed. If the transversal filter is to be mounted on a monolithic chip, this would mean that it would be necessary to inventory a different chip for each of the different functions that are possible. Such a large inventory is impractical.